Nephrotic syndrome is characterized by the following laboratory findings: proteinuria > 3.5g/24 hrs on 24-hour urine collection, proteinuria on urine dipstick, and urine protein/creatinine ratio > 3. When nephrotic syndrome is diagnosed (proteinuria > 3.5 g/24 hrs), additional laboratory tests are required such as serum albumin concentration, serum chemistry panel, lipid panel, and serum creatinine concentration.

For the diagnosis of nephrotic syndrome:^[1]

• 24-hour urine collection shows proteinuria > 3.5g/24 hrs
• Urine dipstick confirms proteinuria
• Urine protein/creatinine ratio > 3

When nephrotic syndrome is diagnosed (proteinuria > 3.5 g/24 hrs), the following laboratory evaluation is needed:^[1][2]

• Low serum albumin concentration
• Serum chemistry panel is generally normal. Pseudohyponatremia due to hyperlipidemia may be present.
• Abnormal lipid panel
• Normal/elevated plasma creatinine concentration
• Urine culture and antibiogram
• Bone profile and corrected calcium concentration

Other tests may be necessary to rule-out secondary etiologies of nephrotic syndrome:^[1][2]

• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
• Fasting plasma glucose
• Antinuclear antibody (ANA) panel
• Anti-dsDNA antibodies
• Hepatic enzymes
• Serologic tests for HBV and HCV
• HIV screening test
• Rheumatoid factor
• Cryoglobulins
• Complement C3 and C4 levels
• VDRL or RPR
• Serum and urine protein electrophoresis